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PHC PARALLEL HYBRID EVAPORATIVE CONDENSERS
Water Treatment and Passivation
Proper water treatment is an essential part of the maintenance required for evaporative cooling equipment. A well designed and
consistently implemented water treatment program will help to ensure efficient system operation while maximizing the equipment’s
service life. A qualified water treatment company should design a site-specific water treatment protocol based on the equipment
(including all metallurgies in the cooling system), location, makeup water quality, and usage.
“White rust” is a premature failure of the protective zinc layer on hot dip or mill galvanized steel which can occur as a result of
improper water treatment control during the startup of new equipment. The initial commissioning and passivation period is critical
for maximizing the service life of galvanized equipment. EVAPCO recommends that site-specific water treatment protocols include a
passivation procedure which details water chemistry, any necessary chemical addition, and visual inspections during the first six (6) to
twelve (12) weeks of operation. During this passivation period, recirculating water pH should be maintained above 7.0 and below 8.0
at all times. Since elevated temperatures have a harmful effect on the passivation process, the new galvanized equipment should be
run without load for as much of the passivation period as is practical.
For more information on water treatment and water chemistry guidelines, refer to the “Operation and Maintenance Instructions”
bulletin supplied.
